Lockable plugging system are known, which protect from unintended release by locking devices such as a plug-in connector and a mating connector that connect axially by a sliding process. The plug-in connector usually includes, in detail, a plug head, on which a sliding sleeve is arranged so that it can move axially, to act as an unlocking device for the plugging system. The sliding sleeve moves in a sliding direction, leading away from the mating connector, to release the locking device of the plugging system. Such a fast lock, which is locked or unlocked by a sliding process, is also known by the term push-pull. The plug head and sliding sleeve of the plug-in connector move against each other by short distances, so that a lock, e.g. in the form of latching hooks and recesses, locks during plugging. For instance, when the plug-in connector moves through the sliding sleeve, by appropriate shaping of the sliding sleeve and the latching hooks of the plug head, the latching hooks lift out of the recesses in the mating connector and unlocking the plug-in connector.
German Patent DE 102 36 275 describes such a plugging system having a known locking device. The described plugging system includes a plug-in connector and a mating connector that can be joined to each other, the plug-in connector having a plug head with an axially movable sliding sleeve. The plug head further includes a hollow body with two locks which extend in the sliding direction, and which have, at their free ends, latching hooks to engage with a latching recess of the mating connector to lock the plugging system. The sliding sleeve includes a recess that corresponds to the lock, and into which the lock extends when the plug head is plugged into the sliding sleeve. The recess of the sliding sleeve is limited by a diagonal surface, the inclination of which corresponds to a sliding diagonal surface of the free end of the locks, so that in the fitted state of the plug-in connector the sliding diagonal surfaces of the lock lie on the diagonal surface of the sliding sleeve. By axial movement of the sliding sleeve, the lock is lifted and put into an unlocked state, so that the plug-in connector can easily be pulled off the mating connector.
However, slight twisting of the sliding sleeve can occur while the sliding sleeve axially moves to release the plug-in connection, resulting in uneven lifting of the locks, resulting from the play which exists between the inner surface of the sliding sleeve and the outer surface of the plug head. Consequently, the latching hook of at least one lock can remain in a locked state, because the latching hook of the lock is not lifted sufficiently out of the latching recess of the mating connector. A locked state here is understood to mean that a latching hook stopper surface is covered by a fastener surface of the latching recess, so that the latching hook and the latching recess cannot move freely in the axial direction relative to each other.
Because of the uneven lifting of the locks and the resulting remaining locked state of at least one lock, the plug-in connector can only be released from the mating connector through a correspondingly greater effort, which overcomes the locked state. This can also result in a break in the region of the latching hook of the lock and/or in a region of the latching recess of the mating connector because of a resulting moment to release the plug-in connection by overcoming the locked state, so that the latching means of the plug-in connection would be damaged, and the plugging system or a corresponding part of the plugging system would have a limited lifetime.